The invention relates to an aircraft air conditioning system and a method for operating an aircraft air conditioning system.
An aircraft air conditioning system is used to adjust and maintain a desired pressure, a desired temperature and a desired air humidity in an aircraft cabin. Furthermore, the aircraft air conditioning system supplies adequate fresh air to the aircraft cabin to ensure that a prescribed minimum amount of fresh air is present in the aircraft cabin. From EP 2 735 510 A1 and US 2014/0144163 A1 an aircraft air conditioning system is known in which a refrigerating apparatus operated using a two-phase refrigerant is used to cool ambient air compressed by a multistage compressor. The refrigerating apparatus comprises a refrigerant circuit, arranged in which are a compressor, a condenser, an expansion valve and an evaporator, through which ambient air that is to be cooled flows. Bleed air taken from an engine or an auxiliary engine of the aircraft is used to drive the compressor of the refrigerating apparatus and to drive the multistage compressor for compressing the ambient air.